Synthesis, Supramolecular Behavior, and In Vitro Photodynamic Activities of Novel Zinc(II) Phthalocyanines "Side-strapped" with Crown Ether Bridges

• Published in: Chemistry, an Asian journal an Asian journal, 2013-12, Vol.8 (12), p.3063-3070
• Main Authors: Chen, Xing-Wei, Ke, Mei-Rong, Li, Xing-Shu, Lan, Wen-Liang, Zhang, Miao-Fen, Huang, Jian-Dong
• Format: Article
• Language: English
• Subjects: Chemistry; crown compounds; Crown Ethers - chemistry; Indoles - chemical synthesis; Indoles - chemistry; J aggregation; Macromolecular Substances - chemical synthesis; Macromolecular Substances - chemistry; metal ions; Molecular Structure; Organometallic Compounds - chemical synthesis; Organometallic Compounds - chemistry; Oxygen; photodynamic therapy; Photosensitizing Agents - chemical synthesis; Photosensitizing Agents - chemistry; phthalocyanines; Zinc
• ISSN: 1861-4728; 1861-471X
• DOI: 10.1002/asia.201300594

Two new tetra‐ or di‐α‐substituted zinc(II) phthalocyanines 5 and 6 have been prepared through a “side‐strapped” method. In the molecules, the adjacent benzene rings of the phthalocyanine core are linked at α‐position through a triethylene glycol bridge to form a hybrid aza‐/oxa‐crown ether. The tetra‐α‐substituted phthalocyanine 5 shows an eclipsed self‐assembly property in CH2Cl2 and the effect on the di‐α‐substituted analogue 6 is significantly weakened. Furthermore, the crown ethers of these compounds can selectively complex with Fe3+ or Cu2+ ion in DMF, leading to formation of J‐aggregated nano‐assemblies, which can be disaggregated in the presence of some organic or inorganic ligands, such as triethylamine, tetramethylethylenediamine, CH3COO−, or OH−. In addition, both compounds are efficient singlet oxygen generators with the singlet oxygen quantum yields (ΦΔ) of 0.54‐0.74 in DMF relative to unsubstituted zinc(II) phthalocyanine (ΦΔ=0.56). They exhibit photodynamic activities toward HepG2 human hepatocarcinoma cells, but the compound 6, which has more than 40‐fold lower IC50 value (0.08 μM) compared to the analogue 5 (IC50=3.31 μM), shows remarkablely higher in vitro photocytotoxicity due to its significantly higher cellular uptake and singlet oxygen generation efficiency. The results suggest that these compounds can serve as promising multifunctional materials both in (opto)electronic field and photodynamic therapy. Side effects: Two novel zinc(II) phthalocyanines “side‐strapped” with triethylene glycol chain(s) have been prepared. The compounds can selectively complex with Fe3+ and Cu2+ ions, leading to J‐aggregation. In the presence of certain ligands, the ions are extracted, thus resulting in disaggregation.